Improvement in the manufacture of salt



UNITEDV STATES PATENT Ormes.

.Jesi-:er1v n. nUfcHANAN, o r vLoUisvlunn, KENTUCKY.

IMPROVEMENT I N THE'MANUFACTUREO'F SALT.

Speciliehtion Forming pnitfot' Leiters Patent No. l07,66, dated OQOleI 'if 157iproduction ot' salt bybu'lling more economical by removing all the `difficulties in the way of using the latent heatl of' steam vas the agent for .successive evaporationa, translerring the same -.lieat from one boiler to another; also, ,to carry this process of transfer of latent heat'through successive evaporations farther than it has .i been carried bef'ore by au apparatus sofcon'! structed as to effectevaporations at very high and verylow temperatures, and thereby render possible more numerous transfers of' the saine caloric. The-higher temperatures and pressures are practicable b vusing strong tubular structures to` contain the condensing steam, and the lower temperatures are niadepractieahle by the reduction ot' pressurl-l in the coiulensing-vessels untilit approximates a l vacuum. Theincrustation ot' calcareous matter-is prevented by removingthe snlphate'and carbonate ot' lime from the lime by heat, het'ore evaporation commences, and the incrustation ot' salt is prevented in aportion ot' the' boilers by stopping at saturation, and in the remainder Vby the elongated vertical structure' of the boilersand comlensing-tubes which secures a f'ree and rapid current along the evaporatingsurfaces. The `deliveryand removal ot' the salt are also effected with greater economy and convenience by meansV ot'- the vertical eraporatoils and the salt-carrier which is vdescribed.' The bi'ne, after undergoing such chemical'trez'itme ,it as its peculiarcomposition mayA require, th" details of which are well known and neednot' be described, is purified by carrying it through a high-pressure heating apparatus,` Figure l, in which its calcareous elements are precipitated, and is then carried through high-pressure and lowpressure boilers, in the `tormer of which it is concentrated by evaporation nearly to the state ot' saturation, and inthe latter is evaporated completely and deposits the salt. Thesteam formed in each boiler bythe process oll evaporation is con veyed totheboilernextin succession, end entersatulml-arstrnctnre,inwhichitiscondensed,

| and asitcondenses causesebullition by the'heatV it gives oli'.- Itfis theudischarged as ivaterby the expulsive forceV of the steam through an automatic pump arrangement, by which it heats and returns to the boiler an amount of brie equal to' what'has been evaporated.

First, the puriier, Fig. 1,consistingot`a cyliudrical vessel, in which the brine is heated and deposits its calcareous elements, and a pump which propels the brine through tubes to and from the heating-vessel. l) propels the brinethrough the supply-pipe l) sp and the brine-channel b c into the heated cavity of' the purifier., and as it passes it is heated by the pipes r t r t r z-, which conve;r the returning brine. As it enters it descends around thecentral cylinder, U C, receiving additional heat from a coil/ot' heating-pipe, l1. p la` p, by which its tempera-ture is maintained at or above 8000;]3lahrenheit. `Thistemperature compels theprecipitation ofthe sulphate and carbonato ot'limc, which, falling to the bottom,-

are received, for convenience, upon a lining ot' cloth oroth'er suitable substance, which may be removedas often as the accumulation may -render it necessary.` The brine, then ascending` through the central cylinder, C C, is prevented from carrying up any of the precipitated calcareous matter by a set of diaphragm-filters ot' fibrous material, dfclfrlf, through which it is compelled to pass. lt then passes through the returning-tubes r t i t r t and heats the incoming brine, and is` received by the pump p 1i, which it enters through a slide-valve, s r, and leaves through another, by the operation ot which the pressure is maintained and the generation of' steam prevented, as. the same quantity ot' brine must be propelled to the .puriiier-b5` cach stroke of the piston,which is withdrawn by the saine stroke, during which the escape ot' .the brine through the pump is prevented by the valves.

Second, the furnace and healer. 1 construct a-i'urnacc on an economical and peculiar plan, and place in it a boiler or heater ot' tubular construction, capable oieuduring a very high pressuresay onethousand poundstoaninchand generating` steam with economy. The steam-pipe' p' l'rcm this heater conveys steam to theinterior of the spiral coil ot tubes b t b tin the first boiler, whicl1,as it condenses,returns through the pipe r s p, which connects with The pump p the'lower extremity of thetubing. ,(See Fig. 4.) The furnaceboiler and the steam-heaters-.of' each brine-boiler are eonstructedidthis pvverful manner of tubes capable of bearingvery high pressures, which structure renders itp'o'ssible to use high temperatures, and thus e'ect greater economy. When Ait is-.vdesired tov increase the rapidity of ,evaporation and the economy resulting from theuse of very high temperatures, I use in placeof steam. a pyrostatic liquid capable ot' undergoing without ,ebullition a temperaturef over 5,50o Fahrenheit.' For this purpose I use the residua-ry. uuid from the' distillation 'ot' petroleum,coin `mtmlyfcalled` petroleum-tar, after the lighter oils, the solid,-?., and 'the 'paraffine have beenv removed by distillation and other means, and the crudeoarbonaceous impurities are removed by filtration; andiu'orderto improve the pyrostatic qualities of the said -liquidI add cans tic soda or potasse, or other saline and alkaline mixtures producing neariy the salmeelects, sol that high temperatures` muy be usedwitho'ut the production of vapor or pressure ordecomposition into-gases. When a pyrostaticliquid isused iuplace of steam I- causeits 'circula` tion by suitable pump (piston or rotary) through 'the tubing in the furnace andin the irst boiler, with the eiect of procuring a higher' temperature' and more rapid' ebulli'tion than canbeproiluced bysteain even 'of a'thousand f iouuds pressure to the inch..

Third, the' coucentrators. Y'llo'.,prcduee salt. 'withtheg'reatest convenience and .economy I. use aset'of high-pressureboilersfto conceu 'trate/the, brine to the point-ot` saturation, or near it',.an il a set olf .logwpress'urefboilers or evaporators to complete the pro'eessfyv-ith the concentrated brine. Thehigh-pressure boilers or con'ceutrators may.b e :from .two-to four in number, or, if 'very high'temperaturcs and pressurcsare used, (aslwith the'use' ojygestat'ic caloriferous liquids as many-,a8 ti elv'e or lteen'may `be combined in succession, allj sustained in operation from one fun'egce.y This more extensive combination and :economical transfer of heatwill beadopted when the price of fuelisvery high in proportion lto the cost ofcoustru'otion ofthe apparatus.- 'lhelow-l pressure boilers, asa general lrule, should not' exceed threeior four in number, as. they operate nearly at or' below the atmospheric pressure.' Y It' the brine should be very 'wettige-larger" number ot' the concentrators will be'required' in proportion; if'half saturated, th`e.conceittrators and vevaporatorsshould' be equal'u'g number; if-'fully saturated, e\ "apcretors.,alonev are used. l

The operation lof' the' apparatus iwnaki'ng' salt'nmyth us lie-described.' K

The boilers beingproperly arranged antigeenn ected in succession fnoi'n'the li'rst tojthe last, those nearest to the furnace aroused as concene trators,a`sthosemostretnotgeseva'poratosLthe" relative number beingdetermined' by' q u'tlityfA 'ofthe brine. 1f the requisite'number ofeirapci highest pressure will be more compactly and 'strongly constructed. The furnace being red, the lleatingltubes in boiler No;1,'B',(sce ground plan, Fig. 7.,) carry a temperature ot' from 4000 'to 8000, according to the plan adopted, and evolve with great rapidity high-pressure steam, which, as it ascends, passes from .the top ot' the' boiler through the steam-pipe S5102. to boiler No2 2, B2, in which it entersthe boiling-tubes b tb t, andgeneratcsanequalquantity ot steam of a lower pressure and temperaturees it condenses in the tubes, andthat steam,.passing in the same manner to the third boiler ,repro duces steam again, and this process is thus rcpeated fromrboiler to boiler tothe end of the series with successively-dimmishing temperature. 'The steam thus condensed in the boiling-tubes, forming hot vwater, is-expelled by the pressureof' thesteam through .the 4brine-v 'pump bp, Fig. 2, which receives the'hot water whenever the valve fo, governed by the tlont, opens as'the water accumulates. When `the water'hasbeen expelled the Iloat F descends and lgeepsthe valveclosed until the water again accumulates' )As thepressnre of the outgoing hot water propels the piston from one end Vof the brine-pump, an equal' amount ,of brine is propelledfrom the other end of the brine-pump into theT boiler, the expulsive force ofthe water froin'the steam-pipes being,r greater `than the resistanceot the pressure inthe boiler. The brine being concentrated nearly .to saturation,- the discharging oatvalve do is opened gravity as to rise whenever thefbrine has nearly reached saturation. The outliow of the :Taturated bri neis compensated bythe inllow offresh' .jector or other suitable automatic device,when-A yby theupper heat, 'u f, the valve of the steampipe'vrhich supplies theinjectr fu f of .Y The saturated'brine, impelled by the pressure 'of the boiler, flows through a'discharging-pipe, dp, `to a pressure-reservoir, P C, from which lit iorvsfinto the low-pressure boilerswhen ,their valves opentoreceive it; The boiling?` tubes of the high-pressure boilers or-"concenin the lower' part' of thef boiler, .with vertical tubes inserted in it by their lower extremities;

. coil,' which latterarrangcment will necessarily be adopted in the f irst boiler "when pyrof static 'liquids ,are`us'cd.' j; Another fp eculiarity' vvill be embodied in `the boiling-.tubes on account of the-dii'erence'between boiling saline solutions? and "boiling simple water viz.',. 1a

serted in the. middle of the horizontal boiling -tube,'rand the steamfpipelwhich enters 'the f .b'oiler'will be connected with thefbottorn of said tube,so1that.thesteam shallenter in the 'water of'condensation and bubble through the 'perforations of .thediaphragm It it is courotors be .more than three' or four-those of thel by the oat I2, which lis so adjusted `in its brine, automatically impelled by a Giffard in#V ever thelevel ofthe brine descends, and opens;

tratois m-ay be constructed like those of the evaporators-viz., a horizontall circular tube Orthey may be'constructedin asingle'spirat lnected directly to .one 01j theverticalf'tubes, that R rousse s tube must'pass in `beneathV thc diaphragm. This arrangementis necessary to facilitate the evaporation of saline solutions, as it reduces the` s uperheated steamof such solutions to the saturated condition, and thereby removes anobstacle to 'the rapid transt'erA of'thelatent heat. `The respective temperatures and pressures of the diii'erent boilers'inay be arbitrarily fixed and regulatedby pressure-valves located on Veach steam-pipe before entering the boiler at 'U or on eachfwater-pipe for condensed steam at itsjexitt'rom the boiler c; but these vali-'cs are no t essential or necessary, as the temperatures and pressuresin such a series ot' boilers will sImntaneOnSIyarrange themselves in regu- Vlar gradation` from the highest to tliejowest,

the gradation being` equal except where the extent of evaporating-surfaces diii'ers from one boiler to another. `Inthe present sketchthe interval of gradation will besmalle'r between the large boilers or evaporators than between `the small boilers or concentrators.

`Fourtlnthe evaporators, Fig. 3. The boil ers, which operatetcn the concentratedbrine,

"are ot' lowertemperatures and pressures, and

therefore more convenient for the delivery of t the salt, and maybe ot a lighter and cheaper structure. The eiaporators employ the heat-` ot' the steam not onl y in their boiling-tubesiut on the exteriorsurtacesot' the boilers. The

steam passes', through the boiling-tubes into.`

the `space 'between thev boiler and the steamjacket S1 J, and is` condensed on the outer surfaceot' the boiler also. The condensed waterat the bottomof the steam-space is removed by the brine-pump, which is impelled,

t not by the force uot' the water passing outfbut bythe force ofthe brine passing in from the pressure-chamber AP C. These evaporators, having both exterior and in terior condensingsurfaces, and-being larger in diameter, have more evaporativepowerand require less elevation ot' temperature for their heating-steam. The tension ot' the steam becomingin some of t them less than atmospheric pressure, they mustbe censtructedto resist external instead ot' in-4 ternal pressure. From thelastei-aporator the vaporis conducted into a coil of tubing', which descendsinto a vat of brine, N,Yand surrendersitsheat, the water of condensation-.being pumped out. The admissionof -brincto thc evapora-tors is" governed by a oat=va1ve, fr, which opens as thc'iiloat descends on the surface of the brine and allows the brine'irom the pressure-chamber l O to force its way iu through brine-pump!) p.' Thet'orce with which the brine 'enters enables the brine-pump to ex- `tractathe waterof condensation from the bottom of th`e steam-space, Whereit collects. The

steanrjackets ofthe low-pressure evaporators. may be constructed of woodor any convenient material, as they require `no great strength,

anda non-conducting `investment ot'- sawdust or other slow conductor should be placed around cachot the boilers and 4the puri'lier,

the strength of the boilcrs'increasin g as they y approachnthe furnace, and the iirstcoucentrat-A or maybe reduced tc t'ro'uicigllt to twelve inches in diameter'ivhen the highest temperatures,

are used.

-Fii'th` the salt-carrier. The salt formed in the evapora-tors may be produced more rapidly or slowly by changing the amountof surface in each, and the quality otsalt, as tine or coarse, determined accordingly. In the ordinaryoperation the rapid current of ebullition carries the salt upward as it is fornild. andcauses its descent in the center ot cachevaporator.v The salt, desceridi|ig,ialls to the bottom and passes through thefunnel-shaped outlet and iscaught in the salt'carrier S C. rlhisis constructed so that it may bereauily discharged by opening the bottom 'valve, B c. It connects with the evaporator by a'slidingjoint, j, or neck, and the junction 'is eii'ectcd by lil'ting the platform P 1f, on' which the salt-carrier stands, by a-suit s ablelever. When a boiler'ot' positive pressure, ahovethe atmosphere, is use das an evaporator, the joint is secured by danges pressed together, f

as shown atFig. 6.A The communication ofthe 'evaporator with the salt-carrier is closed when the latter is illed by litting the conical valve c o with thev valve-rod or by the lever L. -lf

the pressure in the' boiler be more than atmos- ,pheric, it is suspended by shutting oft' the supply ofsteam through the steam-pipe S p and directing it to the next succeeding boiler, for which purpose a connecting-pipe, c p, unites the steam pipes of the adjacent boilers, and

cochsc o are suitably placed to control 'ande change the connection. As one salt-carrier is disconnected another completely filled lwith brineis put in its placeand the loaded one is re-A moved oirthe wheels which support it, as shown inthe drawings. This method otisolating boil ers from the series to which they belong res moves allr the diiicultyof using a detachable salt-carrier in connection with a system of high- ,l

pressure boilers. Saturated brine may4 theref fore be treated by an apparatus consisting cxclusively. of eyaporators constructed with 'the strength necessary for bearing high pressures, and lall the external surfacesconvex. L

struct my entire. apparatus of enameled iron,

and toinyest il:- with anon-conductingluyerof. sawdust (rendered incombustible when used nearthe furnace by alkaline silicates) contained in `an investmentof tin-plate, Russes sheet-iron,j \vood,.or any other suitablem'ate- Ilallz l. i.

To completel my specitication Iannex la defscription ofthe drawings. Figure 1 represents the purifying apparatus`for removingthe sulthe pump by force of theinterior pressure produced by the high temperature. y. bv`c,vthe brine- It remains only to addthat I propose to con-,-

` and the returning-tubes Mfr t convey the re-' opening the puriiier`,the bottoni being detached `df, thediaphragrn-tiltersrremove'from the asis the steam-pipe,whichimparts'steam and pipe`,.conveysthe brine from the pump to the -inot chan nel', conveys thccold brine to the purifier,-

turning and heated and puri-lied brine, which is withdrawn through the pipe rp; hp hp, the heatingpipe, which is heated by steamfrom the furnace-boiler, (or by circulation of pyros'tatic iiuids,) maintaining the requisite heat in the brine as itp-,isses downward in the purilier. G C, the central cylinder, receives' the ascending brine asfit risesfrom the bottoni and passes out'through the returningtubes rt r t. lz' Zt', the lining,r of cloth, receives the precipitated calcareous matterv which falls upon it, and is removed,when necessary, byv

by unscrewing the-hinged fastenings y y. dfy

ccnding brine all impurities which are in suspension. They are constructed ofanysuitable fibrous material.

Fig.2exhibitstheconcentratororhigh-press-- nre boiler, of which h b p is a vertical section'. The number of these vessels combined in an, apparatusinay vary from three or'four to eight or tem-,according to the qualityof the brine and the temperature employed in boiling. S19V caloric to the tubular structures of' the boilers. lihe boiling-tubesb/t b tand-S p2 carries the steam generated in the boiler tothe next sucneeding. boiler. U p is the connecting-pipe, b v means'ot' which, when the steam .is Vshut off from the boiler-through Sp2., by turninga cockL cb, it may. passraround into the vent S152 and be deliveredinto the next succeeding boiler. lil. d 'is a metallic diaphragm or perforated metal plate,v located inthe horizontal boilingt'ubeanddesigned to compelthe steam which. is admitted underit to pass through the Water of condensation .contained in the said tube, wlierebyit is reduced from superheated to rsaturated steam. and its condensationfaeilitated.' Wp is the Water-pipe,whicli conducts the' water from the horizontal tube j ust mentioned toward the brine-pump b p, and carries it on from b p througlithe tube which bringsin thecold brine. Fis a float', andft` the oat-valve,'which allows the Water to be discharged when' it accumulates,and which closes when a certain amount 'has vbeen discharged from the boiling-tubes.' bp, thebrine-pump, moves whenever the 'eX- pelled vater reaches it, impelled by the steamlpressure-of the boiler. bs p, the brine-supply1 boiler at each upstroke ofthe piston in quan-y` ti'ty equal to Vthat of the Vwater ot' condensation. We, the weight, on the piston-rod, causes its descent by gravity and expels the'Wa-teLOf' condensation below as itdraws inthe brinev above. The water-tube w-t-,it will be observed, passes out through the center ot' the brine-supply'tube and imparts theheat ot'ahe Water to tbeincomingcold brine. F2 is aiioat in they boiler, which is adjusted to rise when 'the water approximates saturation and open the 'discharge-valve d i), by which the brine ypasses .ses

conducted to the pressurelcharnberP C, which Ysupplies the evaporators. 'G I represent a Giti'nrd injector for the supi'ily'of` brine tothe `boiler. S p3. is -its steampirie, and bhs'pis Hits supply-pipe for brine. U fis the upper float, 'y'vhich governs the v'admission' of steam tothe injector by the upper float-valve, u f fv.

Fig. 3 represents the-'evaporator or lowpre'ss'ure boiler, ofV which lthere may be a greater Vor less number, in proportion to the strength of the brine. If the number be-more than. three orfour, the s team-jacket-may be vomitted* from-tho additional ones v:of higher presso e, or must'be made ina strong and substantial manner to bea-r'higher pressure, the exterior beingentirely convex.. lp b shows -the section of the boiler; sj, the steam-jacket;

Vb. t. b t, the -boilitig-ti1bes,f\y Sep', the ASteampipe to supply them risp?, the steam-pipe to'discharge steam fromv theboil'er to theboiling-tubes of thenext md-Cp, the connecting-pipe to carry the ls'teai'nfbeyond"the boiler W19,the,condensedevvaterfppe; bp, the brinepump, whichin thisca'seis impr-lied, not by 'the water` of condensation; but by .the brine from the pressure-chamber, b s p, thebrin e supply pipe ajfthejnpper Hoagland u f 'v 'the ipperfrioat'valve,which govern the admission of brine, allowing', its admission as the level of the brine descends. C, the salt-carrier, receives the'salt Vas,fo1`fmed,"which de scends through the funnel-shaped hottom ot' the boiler.v Uv; theconical valve; closes., the passage when lifted by the conical-Valve rod c vi', moved by the lever .L' Wb yW h, the wheels onwhih thesalcarricr rests, 'and on which it isremoved when iiled b i1, the bot- "tom valveffor dropping ont `the`-contentsofthe salt-carrier; j, the slidingjointv by vvhich the salt-carrier connects With the evaporator.'

` In Fig. 6,' Fjis a flange-joint, to be used between' the salt-carrier and the evaporator when the steam inthe latter is' much above the atV inospheric pressure; y, the yoke, and-S c the screw to hold the Bange-joint tight; Pil, the platform on'which -the wheels of 'the salt-,carrier rest, and is lifted by a lever toonnect the joint.A

Fig. e represents the rst salt-boiler: S p" is `the steam-pipe leadingr from the boiler or heater in the -urnace to thejrst salt-boiler; P, the location of thepump 'that may be use d when hydrocarbons are required forheartingy; ii s p, the return-steani-pipe, by which the-Water ot condensation returnsjto'tieheater or boiler in the furnace; b t b' t, the'boiling-tubes, consisting of a spiral coil,`which is aconvenientforni for the boiling-tubes, and may befused in 'place of the vertical tubes wheii-preferred,but offers Igreater obstruction; to, the movement of the water vand escape of the steam,"an'd would be lobjectionable in the salt-making boilers. The use ofan extremely high'pr'essure tube-boiler in the furnace and of high-pressure condens-A ing-tubes in the series of boilers is the leading into the vdischargin'gr-pipe dppby whichv it 'is practical feature of tbsfinvention.

Fig. 7 is the'groun plan. for an apparatus of: eight boilers." Flu, isthefurnace; B1 BZB3 B4 B5 B6 B7 `B8, the boilers, the rst Your being high-pressure; -P lutile purifier; B c-,ppressurechamber; C e, the condensing- WWE y), an

exhausting-pump for `the condensi'n,gr-wat 3 and other structures; j' t, a flexible tuberto be used from the pump for exhausting any ot' thesteam' spacesor tubes .whennecessary` Y,

` What I claim as nen',andde'sire to secnre'by Letters PatentgisQ- 1. The process of the production of' saltj'rom f brine by lhighfpressure.concentradas, and the combination therewithjof lowfpressure evaporators,"constructedsubstantiallyas described. i brine for the produc-j 4tion of salt in highpressure boilers at tem.-

- 2; VThe evaporation of peratures' between 3000 and 600o Fahrenheit,

n andthe transmission of the caloric by successive eva-porations and transfers from these high temperaturesfdown to temperatures bef,lourllOQFahrenheit.`

`3. The-.construction oi' the vertical .boilers "and verticalsystem ot' tu bing, in combinatiom 4 substantially as described to producev rapid and unobstructed evaporation ot brine.'

4. The construction ofthe purifier and its i, associate parts. substantially as described,

Wherebyto produce `the remoyal'ot' the sul-v4 phate and carbonate of lime at the temperature of 'aboutBOOClwitli buta small expenditure of heat.

5. Theconstruction ofthe cvaporatrors, substantially as described, with interior steamtubes and exteriorsteam-spaces, to produce evaporation..

\ f l Y 6. The combination of brine-pumps with thc high and low pressure salt-boilers in such a manner as to inject the brine automatically by the same movement which removes the water vof condensation, substantially as described. 7. The combination, With'the low-pressure evaporator, or Witlrthe high-pressure boiler which ev-apoiates by heating-tubes, but may be promptly relieved of its pressure, ot' a detachable Asalt-carrier connected by a sliding jointA and moving` on wheels, substantially as described. l 8. The use of -puriiied petroleum-tar and its combination with alkalies or their equivalents Yas a medi unl for transmitting heatfrom a furnace .to a boiler.

i). The combination of a-'pressure-chamber with a system of high-,pressure and low-press ure brine-boilers, 'substantially as and for the Ypurposes described.

:10.` The reduction oi' superheated brine-va- 'ing tubes and the combination of a seriesthere- ,of to produce successive evaporations oi' brine by transfer ofthe saine caloric at temperatures above the ordinary boiling-point. Y

" J. R. BUCHANAN.

Witnesses:

A. M. S'roUr, Jr., (5. O. WILSON. 

